Get the absolute value of a number in Javascript

Question

I want to get the absolute value of a number in JavaScript. That is, drop the sign. I know mathematically I can do this by squaring the number then taking the square root, b

Answer 1

Here is a fast way to obtain the absolute value of a number. It's applicable on every language:

x = -25;
console.log((x ^ (x >> 31)) - (x >> 31));

Answer 2

Alternative solution

Math.max(x,-x)

let abs = x => Math.max(x,-x);

console.log( abs(24), abs(-24) );

Also the Rick answer can be shorted to x>0 ? x : -x

Answer 3

You mean like getting the absolute value of a number? The Math.abs javascript function is designed exactly for this purpose.

var x = -25;
x = Math.abs(x); // x would now be 25 
console.log(x);

Here are some test cases from the documentation:

Math.abs('-1');     // 1
Math.abs(-2);       // 2
Math.abs(null);     // 0
Math.abs("string"); // NaN
Math.abs();         // NaN

Answer 4

I think you are looking for Math.abs(x)

https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Math/abs

Answer 5

If you want to see how JavaScript implements this feature under the hood you can check out this post.

Blog Post

Here is the implementation based on the chromium source code.

function MathAbs(x) {
  x = +x;
  return (x > 0) ? x : 0 - x;
}

console.log(MathAbs(-25));